This invention relates to heavy duty industrial conveyor rollers (also known as idlers) such as may be used in many kinds of industrial conveyors, especially (but not exclusively) belt conveyors, to bearing housing assemblies for conveyor rollers, and to the methods of manufacturing such assemblies and rollers.
The movement of bulk materials within industry is frequently carried out by means of the utilisation of belt conveyors. Some common examples of materials which are moved by belt conveyors are quarried and mined materials; solid fuel for power stations; iron ore and related materials for the production of steel; and the loading and off loading of bulk materials into and from commercial shipping.
A typical belt conveyor is generally comprised of a moving flexible belt carried over a series of evenly spaced roller stations forming a conveyor track. Such roller stations typically comprise three rollers arranged in a flat bottomed V shaped configuration, otherwise known as a troughing configuration. One kind of known roller comprises an outer cylindrical steel tube having a bearing housing assembly welded to it at each end, and having a central spindle/shaft which passes through the tube, the tube being rotatably mounted upon the spindle by means of the aforementioned bearing housing assemblies. The spindles are supported in any convenient known manner. One known form of bearing housing assembly comprises a cylindrical housing portion having a radially outwardly extending flange at one end, and an annular radially inwardly extending flange at the other end, and inner and outer ball bearing races held in the top-hat shaped housing by means of an annular closure plate provided at said one end. The spindle passes through the central holes int he inwardly extending flange, the ball bearing inner race, and the annular closure plate. The ball bearing race is conventionally lubricated, and a protective seal for the ball bearing is also provided within the structure of the roller bearing housing assembly.
Current known designs of rollers for belt conveyors, including the kind described above, usually work well--but the roller bearing housing assemblies within such designs often deteriorate rapidly and fail prematurely and they are also awkward and expensive to manufacture because of the narrow manufacturing tolerances required. It is difficult to automate the assembly of such bearing housing assemblies, whilst still adhering closely to these vary narrow manufacturing tolerances. Indeed most current designs of bearing housing assemblies are at least partially manually assembled. Furthermore, welding bearing housing assemblies to the cylindrical steel tube is another critical operation because of the same requirement to adhere closely to very narrow manufacturing tolerances. For example, the bearing housing assemblies must be correctly aligned with the vertical face of the cut end of the tube, and at the same time with the central axis of the tube. Additionally both the tube and the spindle/shaft must be cut exactly to the correct length required. Furthermore, the linear distance between the two inner location points upon the spindle must be very accurately controlled. Failure to adhere closely to any of these manufacturing requirements will lead to premature failure of the bearing housing assembly, as already mentioned.